<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        var num = 10;
        console.log(typeof num);//number
        var str = '文本';
        console.log(typeof str);//string
        var flag = true;
        console.log(typeof flag);//boolean
        var vari = undefined;
        console.log(typeof vari);//undefined
        var vara = null;
        console.log(typeof vara);//object

        //prompt 取过来的值是 字符型
        var age =prompt('请输入年龄');
        console.log(age);
        console.log(typeof age);
    </script>
</head>
<body>
    
</body>
</html>